Introduction

This project generate a random password to the user, based on what groups of characters the user want on his password. The user input the parameters and the password is generated. The groups and their parameters are:

  -l, --lower        Add letter in [a-z].
  -u, --upper        Add letter in [A-Z].
  -d, --digits       Add letter in [0-9].
  -o, --logograms    Add letter in [#$%&@^`~].
  -p, --punctuation  Add letter in [.,;:].
  -q, --quotes       Add letter in [\"'].
  -s, --slashes      Add letter in [\/|_-].
  -m, --math         Add letter in [*+!?=].
  -b, --braces       Add letter in [{}[]()].
  -a, --all-groups   Add letter from all the above groups.

As a matter of fact, the user can use the parameter -h or --help to show this mensage about the parameters as a "how to use the program" tutorial.

The user can also set the length of the password with --len parameter. 7 is the default length. Finally, the user can use the --strength (or -t) parameter if he wants to check the strength and the entropy of the generated password.

Author(s)

Haniel Lucas Machado Rocha: hani.lucas70@gmail.com

Theo Henrique da Silva Borges: theo123b@gmail.com

Member Contribution

Haniel

• Created validate_arguments and performed all the error handling in it.
• All the items in the RunningOptions struct in addition to those that Professor Selan had added.
• The mappings that identified the groups of characters corresponding to their flags (flags_with_their_items), and the characters corresponding to their groups (items_with_their_characters). These maps were used constantly throughout the code.
• Doxygen documentation.

Theo

• Created generate_password.
• Implemented the external library zxcvbn.
• Created password_quality using the resources available in zxcvbn.

It is necessary to say that, even though each one did these parts separately, we talked to each other at all times, cleared up doubts and helped with the logic behind what the other was doing.

Problems found

Here we are registering some difficulties doing this project.

To check if all the characters of argv[ct] were digits

In the validate_arguments function, inside the for loop that iterates through the command line to apply the conditions for passwords, when we go to set up the if statement that checks the password length, Theo placed the command:

run_options.pass_length = std::stoul(argv[ct + 1]);

run_options is a variable of the RunningOptions struct, and pass_length is a field in this structure that represents the password length.

This command will define the password length as the string inside argv[ct + 1] converted to an unsigned int. However, it is missing a check to verify if the input after --len is a number. To do this, Haniel tried:

if (++ct > argc || !isdigit(argv[++ct]))

But this causes an error in the second condition because it says that argument of type 'char *' is incompatible with parameter of type 'int'.

One attempted solution was to use if (++ct > argc || !isdigit(argv[++ct][0])) so that it only looks at the first digit. This made the error disappear, but it allowed the user to type something like 1ab, which would be interpreted as a number, even though clearly it isn't.

The solution used is in the code.

An error handling that didn't work:

If the user types something completely random, e.g. gevfaqtheb, instead of usage() being called, the code generates a password with only LOWER (if nothing else is typed).

To create the password generator function

I used the items_with_their_characters unordered map to organize and make the password generation easier, associating a variable that stores a std::uint8_t number. Then, i created a array of booleans to check if the options inputed by the user were true or false.

So i were atributting a password character this way:

password += items_with_their_characters[inc1][inc2]

Where inc1 was correctly incremented to scan the array of booleans, but inc2 were also incremented. The problem was that inc2 determines the position of the character that will be catched in items_with_their_characters[inc1], so it can't be greater than items_with_their_characters[inc1].size().

I tried to do this verification:

if (items_with_their_characters[inc1][inc2] > items_with_their_characters[inc1].size()){
    inc2 = 0;
}

That bring me another problem: I was repeating the same characters of one group before all the other characters were used. Then i finally realized that i must use an vector with 9 zero's initially. Each of the zero's will represent an index, and they will be reseted if index[inc1] >= items_with_their_characters[inc1].size(). This way, the groups will not share the same iterator.

To import the library zxcvbn-c locally

It took me a long time to understand how to correctly configure the includes and find the correct files in the library to import to the project. Also, the zxcvbn-c library is a c-library as default, not c++. I took a long time to realize that i must change the extensions .c to .cpp.

Grading

Preencha os itens que você implementou, indicando qual a nota esperada para cada item.

Item	Valor máximo	Valor esperado
Interface de acordo com o especificado	20	20
Seleciona caracteres dos grupos adequadamente	15	15
Apresenta a tela de ajuda quando solicitado	5	5
Trata os erros de entrada corretamente	12	10
Avalia a qualidade da senha com 5 categorias	10	10
Implementa os 9 grupos de caracteres solicitados	18	18
Utiliza corretamente a aleatoriedade	10	10

Compiling and Runnig

In your terminal, stay on the ".../trabalho-03-projeto-passgen-el-th-hani" directory, and use the following commands:

Compiling:

g++ src/main.cpp lib/zxcvbn.cpp -o passgen -Ilib

We have to compile the code this way because we are using the zxcvbn-c library locally to check the password strength.

Command details:

• g++: Call g++ compiler
• src/main.cpp: Compile the source-code of the program (main.cpp)
• lib/zxcvbn.cpp: Compile the auxiliary code zxcvbn.cpp from the library
• -o passgen: Name the executable as passgen
• -Ilib: Specify the lib directory as a include directory

Running:

Example:

./passgen --len 15 -a -t

• ./passgen: The name of the executable you are running
• --len: --len + Number specify the length of the password that will be generated
• -a: Is the parameter that says that the user want all the groups
• -t: Is the parameter that says that the user want to know the password strength and the entropy